Electronic products such as personal computers, notebook computers, electronic dictionaries, calculators, mobile phones, personal digital assistants (PDA) require an input device for facilitating an input or an operation of the electronic products.
For example, a computer keyboard generally includes an upper casing having a plurality of key seats, a plurality of elastic elements disposed in the plurality of key seats respectively, a plurality of key caps for supporting vertically up and down movements of the plurality of elastic elements, a circuit membrane electrically connected to the plurality of key caps, a circuit board electrically connected to the circuit membrane, and a base for retaining the circuit board. Users can press any key cap, such that the key cap is electrically connected to an electric contact of the circuit membrane, and then an input/output terminal (I/O) of the circuit membrane is electrically connected to the circuit board for transmitting a key code representing the corresponding key cap to a computer system, such that users can observe the results on a display device.
However, the aforementioned prior art installs the key cap and the circuit membrane independently, and a gap is generally formed between the key cap and the circuit membrane, and thus liquid such as water, tea or coffee may permeate directly into the keyboard through the gap and affect the electric properties of the keyboard or cause errors or failures, so that the reliability of the keyboard is reduced. Thus, some manufacturers provide a waterproof function of the keyboard, and related patented technologies were disclosed in R.O.C. Pat. Publication Nos. 200809891 and 200826130, R.O.C. Pat. Nos. M334390, M312718, M281227, M243721, and R.O.C. Pat. Publication No. 553433, etc.
For example, some manufacturers produce a keyboard comprising a main body, a press key body, a conductive membrane and a circuit board, and rubber strips or adhesives are used for assembling the main body and the press key body to provide the waterproof effect. This design mainly uses an insulating layer to cover pins and power line terminals of electronic components on the circuit board, and rubber strips and metal strips are used for sealing the terminals of the conductive membrane connected to the circuit board.
However, the aforementioned prior art can achieve the water-repellent effect only. If the keyboard is dipped into a liquid such as water, then the water still will enter into the keyboard. Furthermore, the prior art requires the aforementioned manufacturing processes and thus incurs a long manufacturing time, and results in rubber cracking, adhesive peeling, and failure of providing the waterproof function.